Storage

Introduction to storage in KVM/libvirt

Storage is a foundational part of virtualization: it determines how and where virtual machine disks are stored, how snapshots are handled, and what performance and protection options are available. In the KVM/libvirt ecosystem storage is organized around two basic concepts: Storage pools: logical groupings that represent a storage source (for example, a directory, an LVM volume group, an iSCSI target or a Ceph pool). Libvirt exposes and manages these pools to simplify storage usage for VMs. Storage volumes: the units inside a pool that act as virtual disks for guests. Types of pools Libvirt supports several pool types. A practical summary:

Saturday, October 25, 2025 | 4 minutes Read

How to manage storage pools

This post answers the following questions and provides practical examples: What is a storage pool? How is a pool created and what forms can it take? Storage in KVM/libvirt is organized using “storage pools” and “storage volumes”. In this article we explain what a pool is, why pools are used, and how to manage them with virsh or XML definitions. We include examples, practical recommendations, and notes about LVM-based pools.

Saturday, October 25, 2025 | 5 minutes Read

How to manage storage volumes with virsh

Short: examples of using the libvirt API (virsh vol-*) to manage volumes inside storage pools and notes about backend-specific behavior. Managing storage volumes with virsh In this section we’ll look at storage volume management using libvirt’s API (the virsh tool). We will use pools of type dir (image files on disk), although many operations are applicable to other backends; differences are noted where relevant. Pools and volumes: quick concept A “volume” in libvirt is the storage unit created inside a pool. In dir and fs pools volumes are files (for example qcow2, raw); in logical pools they are LVM logical volumes; in disk pools they can map to partitions; and in networked backends (Gluster, RBD, iSCSI) creation and management may require backend-specific tools.

Saturday, October 25, 2025 | 6 minutes Read

How to resize virtual machine disks

In this example we’ll use the default pool and a volume named vdisk-10G.qcow2. We’ll show how to create the volume from the host, how to format it with common filesystems (ext4, FAT32, XFS, btrfs) from inside the guest, and finally how to add 10 GB to the volume and resize the partition and filesystem. Note: commands that manage volumes (create, resize) run on the host and use your prompt. Commands executed inside the guest (partitioning and formatting) are shown with the guest prompt javiercruces@debian13:~$.

Saturday, October 25, 2025 | 4 minutes Read